Means for the production of foam



June 16,

J. DYHR MEANS FOR THE PRODUCTION OF FOAM Filed Nov. 5, 1929 PatentedJune 16,1931

UNITED STATES PATENT OFFICE JENS DYHR, F DRE SDEN, GERMANY, ASSIG NOR TOSCHAUMBAD GESELLSCHAFT MIT BIECHRANKTER HAITUNG', OF DRESDEN, GERMANYMEANS FOR THE PRODUCTION Oll FOAM Application filed November 5, 1929,Serial No. 404,977, and in Germany February 21, 1929.-

. Devices are known for introducing ases into liquids in a finelydistributed state. su-

- ally however the fineness of distribution is insuflicient; especiallyin balneology for the production of shower baths, foam baths or in foamtherapy. In the production of fire extinguishing foams also the gasesare usually not sufficiently finely distributed.

Those devices in which metal tubes with slits or perforations for thepassage of the gases are employed are not satisfactory for the reasonabove given. 1 As it is not possible to make the slits or holes narrowenough to ensure a sufficiently fine distribution of the gas, it hasbeen proposed to wrap or enclose such metal tubes in porous materialssuch as linen or fine metal gauze in order to subdivide still furtherthe gases passing through the slits or holes.

' Since naturally V the gas can only flow through those parts of thetubes where the tube wall is interrupted and as for reasons of strengthtoo many slits or perforations cannot be made, only about 50% of thesurface of the tubes is effective for the passage of gas.

In order to increase the distribution of the gas in accordance with thepresent invention there are employed in lieu of the usual round tubes,tubes provided with longitudinal projecting ribs or with deep grooves soas to form with the wrapping of porous material longitudinal passagesbetween the tube wall and the wrapping. If holes are bored at the bottomof the grooves or between the longi tudinal ribs the gas passes from theinterior of the tubes through the holes into the longi: tudinal channelsand thence to the wrapper along the whole length of the tube. Only thenarrow projecting longitudinal edges of the grooves or ofthe ribs wherethey are contacted by the wrapper interfere with the passage of air. Thesurface thus lost is so small as to be negligible. The tube may ofcourse be round or oval and spacing members may be provided between thewrapping and the tube so as to form the longitudinal channels. Anembodiment of the invention showning a tube of star-shaped section isillustrated by a battery of such devices connected together.-

For the sake of clcarness' the tube is shown in Fig. 1 to a veryenlarged scale.

Referring to Fig. 1, along the bottom of the grooves of the tube arelocated holes 2 while porous material is wrapped or coiled around thetube thereby forming a perforated metal wrapper. A metal wire outercovering around the wrapping is indicated at 4. The walls of the tube 1and the wrapper 3 forms channels 5 which lead the gas introduced intothe interior of the tubes and passing through the holes 2 along thewhole length of the tubes.

As the drawings clearly show, almost the entire wrapper may be used forthe passage of air.

A tube having six ribs is shown in the drawings, but tubes having moreor fewer grooves or longitudinal ribs may be used. If the gas is to passout over the upper half of the tube only as is often required, only thebottoms of the upper grooves need be formed with holes. A number oftubes can be arranged in known manner to form batteries as illustratedin Fig. 2.

In that figure three tubes 7 are shown as connected to an air chamber 8in such manner that the air can pass from the air chamber 8 into thetubular members. ,Air is supplied byway of a branch connection 9 whilethe tubes 7 are closed at their opposite ends. The tubes may be heldtogether in their proper positions by means of bar 10.

claim i 1. A device for introducing gas in a finely distributedcondition into liquids for foam forming purposes, comprising a tubeshaped to rovide a plurality of grooves and ribs, sai tube perforatedbetween the ribs to form a fluid passageway, a porous medium envelopingsaid tube, a perforated metal wrapper surrounding said porous medium,and means associated with said tube for creating a fluid pressuretherein, whereby the fluid is caused topass through the porous medium ina finely distributed condition.

way of example in the accompanying draw 2. A device for introducing gasin a finely distributed condition into liquids for foam formingpurposes, comprises a tube shaped to provide a lurality of ribs andgrooves formed para el to the longitudinal axis thereof, perforationsthrough the tube formin a fluid passageway, a porous medium enve opingsaid tube, and means associated with said tube for creatin a fluidpressure therein, whereby the fluid is caused to pass through the orousmedium in a finely distributed condition. a

3. A device for introducing gas in a finely distributed condition intoliquids for foam forming purposes, comprising a plurality of tubesconnected at the ends thereof by conduit which forms intercommunicatingpassages between the tubes, each of said tubes shaped to provide aplurality of grooves and ribs,'each of said tubes perforated between theribs to form a fluid passageway, a orous medium enveloping said tube, aper orated metal wrapper surrounding said porous medium, and meansassociated with said tube for creating a fluid pressure therein, wherebythe fluid is caused to pass through the porous medium in a finelydistributed condition.

In testimonywhereof I have signed my name to this specification.

' JENS DYHR.

